<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Hello React</title>
</head>
<body>

  <div id="root"></div>
  <div id="app"></div>
  
  <!-- 添加依赖 -->
  <!-- 依赖三个包 -->
  <!-- CDN引入 -->
  <script crossorigin src="https://unpkg.com/react@18/umd/react.development.js"></script>
  <script crossorigin src="https://unpkg.com/react-dom@18/umd/react-dom.development.js"></script> 
  <!-- babel -->
  <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>

  <!-- 下载引入 -->

  <!-- npm下载引入(脚手架) -->

  <script type="text/babel">
    // 编写React代码(jsx语法)
    // jsx语法 -> 普通的JavaScript代码 -> babel

    // 渲染Hello World
    // React18之前: ReactDOM.render
    // ReactDOM.render(<h2>Hello World</h2>, document.querySelector("#root"))

    // React18之后:
    const root = ReactDOM.createRoot(document.querySelector("#root"))
    root.render(<h2>Hello World</h2>)

    // const app = ReactDOM.createRoot(document.querySelector("#app"))
    // app.render(<h2>你好啊, 李银河</h2>)

  </script>

</body>
</html>